The old way of distributing products in large distribution packages, followed by repacking of the products behind the store counter in paper bags, or the like, in the amount as bought by the consumer, has almost completely disappeared. Decades ago the wide spread of the large self service stores, with pre-packed products stored on shelves, from which the consumers themselves pick the products, lead to great developments in the packaging industry.
Today almost all consumer products are packed at the manufacturing or processing site, distributed, sold, and often also stored in the consumers' home, in one and the same package. One popular kind of package used for almost all kind of products is a box made of paperboard. Paperboard boxes are, e.g., widely used for dry food products and for small commodity items such as screws and nails. By providing an inner bag the paperboard box may also be used for liquids or for powder products, such as cocoa or dry milk. This kind of package is also widely used for cereals and similar products.
This kind of package is often adapted to be opened by first tearing off a tearing band or strip from the paperboard box and then cutting (with a pair of scissors) the inner bag open. The tearing band often extends across the complete top surface, from side edge to side edge, and separates a front flap connected with the front side of the container from a rear flap connected to the back side of the package. The front and rear flaps are often spot glued to side flaps folded from the sides of the package underneath the front and rear flaps. When the consumer opens such a package the tear band often breaks and the tearing action need to be restarted again. Moreover, the tear band often does not separate from the flaps as intended, which makes it more difficult to open the package and which often results in that any reclosing means, such as flaps and slits, are damaged.
Another kind of package often used as a consumer package is a bottle or jar formed of plastic or glass provided with a screw cap or snap lid formed of plastic or metal. This kind of package has an intrinsic problem relating to the compromise of providing a sufficiently low initial opening force and a sufficiently good sealing. Most caps or lids on this kind of package are fastened by threads or bayonet mount. In order to provide the necessary sealing pressure, the caps or lids must be fastened with a significant torque. Within the packaging industry there exist numerous variants concerning how to avoid the need for application of a high torque for closing the package. However, as will be discussed below, these variants introduce different drawbacks for the consumers when opening the packages, and especially at initial opening of the packages.
One kind of package often used for jam, pickled gherkin, and the like is a glass jar with a metal lid. Such a package is often filled by hot-filling or the like in order to create a negative pressure inside the jar. This negative pressure will force the lid against the mouth of the jar and will thereby improve the quality of the sealing between the lid and jar. However, this way of creating a good seal has the drawback that it is very hard to open such a jar; when trying to rotate the lid, the negative pressure will give rise to a high friction force counteracting the intended opening action. This kind of package also requires that the jar and lid are formed of relatively rigid components in order to be able to withstand the forces involved.
One kind of package often used for dry products, such as instant coffee, is a glass jar with a simple plastic lid. In order to provide sufficient sealing, the jar is, underneath the lid, provided with a sealing film or membrane. Such a sealing membrane is often also provided on plastic bottles for ketchup, mustard or the like, and boxes for table margarine or the like, where the lid has a snap functionality or some other functionality which is difficult to use to provide a sealing action. The film or membrane is often glued or fused to the mouth of the package. However, this kind of package suffers from the drawback that the necessary tearing off force must be sufficiently low so that the user is able to tear off the membrane and preferably in one piece, but the membrane should also be securely sealed to the mouth and it should from cost and environment aspects be as thin as possible. The result is often that the consumer has difficulties in tearing off the membrane at all or in tearing off the membrane in one piece. If the membrane is only partially torn off, it is often difficult to get rid of the remainders since any grip tab or the like has already been torn off.
Thus, the known packages all suffer from different drawbacks when it comes to opening of the packages.
It is well known in the art that polymer chains can be broken by the application of a voltage. This is for example discussed in a review article by G. S. Shapoval (Cathodic initiation of reactions of macromolecule formation and degradation, Theoretical and Experimental Chemistry, Volume 30, Number 6, November 1994).
U.S. Pat. No. 6,620,308 B2 discloses a material for use in the airplane industry. As is evident from the published patent, the material has been developed under the supervision of the U.S. Department of the Air Force. The material is developed for use as coatings and adhesives. It is further elaborated in U.S. Pat. No. 6,620,308 that the adhesive bonds and polymeric coatings are commonly used in the assembly and finishing of manufactured goods. It is stated that adhesive bonds are used in place of mechanical fasteners, such as screw, bolts and rivets, to provide bonds with reduced machining costs and greater adaptability in the manufacturing process. It is further discussed that adhesive bonds distribute stresses evenly, reduce the risk of fatigue, and seal the joints from corrosive species. It further asserts that, similarly, polymer-based coatings are commonly applied to the exterior surface of the manufactured products. These coatings provide protective layers that seal the surface from corrosive reactants, as well as provide a painted surface that can the aesthetically pleasing.
The composition disclosed in U.S. Pat. No. 6,620,308 B2 has a matrix functionality and an electrolyte functionality, wherein the electrolyte functionality is provided by a block copolymer or a graft copolymer. The matrix functionality provides an adhesive bond to a substrate, and the electrolyte functionality provides sufficient ionic conductivity to the composition to support a faradic reaction at an interface with an electrically conductive surface in contact with the composition, whereby the adhesive bond is weakened at the interface. The composition may be a phase-separated composition having first regions of substantially matrix functionality and second regions of substantially electrolyte functionality.